The present invention relates to a device for separating solids from suspension.
The present invention is a so-called twin filtering belt press, wherein the suspension to be filtered is supplied in between two filtering belts travelling in the same direction. The filtrate becomes separated when passing through the belts and the solids in the suspension remain as solid cakes on the surfaces of the filtering belts. Finally the filtering belts are led against each other, at which stage dewatering still takes place by squeezing through the belts.
In conventional twin filtering belt presses, the open construction at the prefiltering chamber formed between the converging filtering belts has heretofore prevented the increase in velocity. For example, there are known solutions, where the filtering belts are supported on the side of the filtrate by means of rollers and edges of the belts are in this case relatively free. At the side a chamber of this type is sealed by means of wedge-like sealing strips, which are in contact with the edges of the filtering belts and hence cause wear of the belts. Further, such a relatively open construction has not allowed to use pressure in the prefiltering stage, and therefore there has not been another alternative than to construct the filtering stage to a big and expensive section.
U.S. Pat. No. 1,875,075 discloses one solution to the above-mentioned problem. However, in this construction the walls supporting the prefiltering chamber from the sides are fabricated of a resilient material, as a result of which the pressure can not be elevated in this case either. Moreover, the sealing at the exit end of the prefiltering chamber is not sufficient.